Generally speaking, any enclosure that is tight enough to keep the snake from escaping, while providing for some ventilation is good enough. You do have to make certain about it being escape proof, though. Too many plastic containers are flexible enough for a corn to get out where you weren't expecting.
As far as the heating issue is concerned, it has been my observation that any heat source which could possible melt a plastic enclosure is too hot to use reliably on a glass tank too. Just provide that aforementioned space (as little as a 1/8" is fine) for air circulation.
Hope this helps